Comparison of characteristics between populations participating in two lung cancer screening (LCS) studies with low-dose chest CT (LDCT) in Pisa, Italy: ITALUNG (ITL) projects

<bold>BACKGROUND:</bold> Participants in LCS may exhibit different characteristics according to selection criteria. <bold>AIM:</bold> To preliminary compare demographic, clinical and smoking characteristics of participants in two LCS conducted in Pisa, Italy, in 2004 (ITL1) and in 2022 (ITL2), and to assess their relationship with positive baseline LDCT outcome. <bold>METHODS:</bold> 351 subjects from ITL1 (randomized trial, enrolled from GPs records, 55-69 yrs, ≥20 pky) were compared with 287 from ITL2 (non-randomized pilot study, volunteers informed by physicians or social media, age range 55-75 yrs, ≥30 pky). Two logistic regressions were applied, with being ITL2 or having positive LDCT (detected ≥1 nodules) as dependent variables, and age, sex, current smoking, pky, lung cancer family history as covariates. <bold>RESULTS:</bold> As compared to ITL1, ITL2 subjects showed significantly (p<0.001) higher mean age and prevalence of current smoking, current occupation, higher education, cardiovascular, respiratory or other comorbidities, lung cancer family history. Pky and positive LDCT did not differed between ITL1-ITL2. In logistic regressions: age ≥59 yrs (p=0.000), female sex (p=0.001), current smoking (p=0.000), and lung cancer family history (p=0.016) were independently associated to being participants in ITL2; no significant predictors were associated with positive baseline LDCT. <bold>CONCLUSIONS:</bold> While two different groups of participants in LCS differ for baseline characteristics, there are no significant predictors associated with a positive LDCT. Further analyses are needed to define those characteristics which may support criteria to select subjects eligible for LCS.